Problem code P0304, can't solve it.........

Edman · Post by **Edman** » Sat Feb 25, 2006 12:40 am

Problem code p0304 is a (miss fire on cylinder #4).....

When you rev the car in "park" , half way down it revs fine. The the last half way down it cuts in and out. I can drive the car fine on the road or freeway, I notice a lose of power up hills at full throttle. I becomes sluggish.

I have replaced all plug wires and the fuel filter. I'm thinking it might be the fuel injector or ignition coil.....

I'm assuming the computer means cylinder #4 (1-2-3-4). Or do you think it means #4 (1-3-4-2). If it's the injector in might be working intermitantly.

What do you guys think?

Edman

MMamdouh · Post by **MMamdouh** » Sat Feb 25, 2006 12:46 am

in this case cyl. 4 is the one closest to the coil pack.

MMamdouh

Post by **PrecisionBoost** » Sat Feb 25, 2006 1:06 am

What do the spark plugs look like?

If there is an injector issue it will show up in the color of the plug in the cylinder that is misfiring.

http://www.dansmc.com/Spark_Plugs/Spark ... talog.html

Here is an excelent site..... perhaps someone with more time could copy the pictures of the plugs into the album and put the description in the "how to" area.

I doubt that it's a coil pack issue.... cylinder 1 & 4 share the same coil on the coil pack.... so if the ignition coil is not firing on 4 it wouldn't be firing on 1 either.

Pull the plugs.... take a look.... if you don't see anything there.... it might be related to the plugs themselves.

Sometimes you can get bad plugs with damaged conductors internally..... I have personally seen brand new "faultly" plugs on three different occasions.

If in doubt..... swap the #4 plug with the #2 plug..... if you get a misfire in #2 it's the plug... or you can throw in new ones just to be sure

Edman · Post by **Edman** » Sat Feb 25, 2006 1:41 am

The first thing I did was replace the plugs. Then the plug wires and then the fuel filter. The previous plugs looked fine......

Thats why I suspect the injector or maybe the coils. I'm thinking more and more the injector! Anyone have a extra one I can test with???????????? Or the car brain?

Thanks, Edman

chronoti · Post by **chronoti** » Sat Feb 25, 2006 4:03 pm

just swap injectors with another cylinder and see if the problem moves to that one.

JohnnyC · Post by **JohnnyC** » Sat Feb 25, 2006 4:14 pm

Have you cleaned your injectors in general? I've heard our Woo's typically have problems with the injectors getting dirty... Though honestly I don't know enough about cars to know if dirty injectors would cause a miss-fire.

katalla · Post by **katalla** » Sun Feb 26, 2006 10:38 pm

i had a p0302 code show up and the car was misfiring all the time i changed the coil pack ,wires, plugs and fuel filter and nothing happened so i tried the injectors i took the #2 injector and cleaned it a little, gave it a few taps then switched it with the #1 injector and that fixed the problem. i put some injector cleaner in the gas and hope it cleans the dirt out, a dirty injector can cause a misfire as i learned yesterday.

Audacity Racing · Post by **Audacity Racing** » Sun Feb 26, 2006 10:40 pm

check the how to section for a HOW TO USE SEAFOAM. so teh seafoam engine clean-up procedure and you'll be good (if it's a dirty injector). you won't spend over 15 bucks for the saefoam treatment and it will clean the system very well.

Post by **PrecisionBoost** » Sun Feb 26, 2006 11:32 pm

If it's misfiring due to injectors it's most likely going to show up as a lean condition on the spark plugs.... which would cause some knock issues.

If the color of the spark plugs were fine.... it's more likely to be ignition related.

Just because you changed the spark plugs it doesn't mean that there is still an issue.... one time when Tom was doing a tune up on a ford truck there were two or three brand new Bosch spark plugs that were complete duds.

Perhaps you might have a coil pack issue where both 1 & 4 are misfiring but only #4 is showing up on your scanner.

I know this sounds stupid.... but make sure your plug wires are on the correct positions.... the engine will still run if they are mixed up.... but it will run poorly.

MMamdouh · Post by **MMamdouh** » Mon Feb 27, 2006 12:03 am

chris@PrecisionBoost wrote: the engine will still run if they are mixed up.... but it will run poorly.

why is that?? is the waste spark weaker than the ignition spark??

MMamdouh

Audacity Racing · Post by **Audacity Racing** » Mon Feb 27, 2006 12:04 am

MMamdouh wrote:
chris@PrecisionBoost wrote: the engine will still run if they are mixed up.... but it will run poorly.
why is that?? is the waste spark weaker than the ignition spark??

MMamdouh

significantly

MMamdouh · Post by **MMamdouh** » Mon Feb 27, 2006 12:08 am

is it weaker because the ECU makes it so or due to the pressure inside the combustion chamber?? if it is the pressure that affect the strenth of the spark then switching cables will not affect how the engine behaves... right??

MMamdouh

Audacity Racing · Post by **Audacity Racing** » Mon Feb 27, 2006 12:16 am

it is the direction of the current being fired... there may only be two sides to the coil, but it fires on 4 independant circuits. the other circuit (NOT the primary one being fired) is the ground return for the coil.

basically, if they wires aren't put right, the majority of the spark energy is wasted on the exhaust stroke of the other cylinder and is weakened as it travels through the plug and head.

MMamdouh · Post by **MMamdouh** » Mon Feb 27, 2006 12:33 am

in this case it is better to stick with the correct OEM setup on the coil pack mentioned here:
http://www.daewootech.com/forum/viewtopic.php?t=2634

MMamdouh

chronoti · Post by **chronoti** » Mon Feb 27, 2006 4:19 am

http://www.autoshop101.com/forms/h41.pdf

may be a toyota based file but fully explaines how the DIS igniton system works.

The original daewootech forum

Problem code P0304, can't solve it.........

Problem code P0304, can't solve it.........

I the plugs have been changed......